Next 16.4 adopts a native history write a render later. A second write inside that gap was undone when the router adopted the first, and a write computed from useSearchParams started from the URL before the last one. Clearing the vault's filters could therefore leave ?encounter= behind: the debounced search wrote the filters it had rendered back over the clear. @/lib/url-state is now the one way a page writes its own query: each write starts from the live address bar, at most one waits for the router at a time, and later updates queue on top of it and go together once the router has it (or after a short grace). useUrlSearch reads the same live value and reports each adoption. The filter hook (documents, measurements, mood), the open document, the day layer, the timeline's zoom and range, the medication tabs, the AI provider choice, the Coach's ?c= and the one-shot parameter strips all go through it; the filter changes merge into the live filters. A guard refuses raw history writes and router writes built from the rendered params outside the helper. The timeline spec now waits for the values menu to hand focus back before scrolling to the last row; it measured mid-animation and the focus return scrolled the page back.
e2e/
End-to-end browser tests. Playwright 1.60 drives a production build of the app against a real PostgreSQL, with @axe-core/playwright for accessibility assertions. This is the heaviest test tier; CI runs it on every PR, and locally it is worth running when a change touches a UI flow.
Running
pnpm e2e
The Playwright config (../playwright.config.ts) builds the app (next build) and brings up Postgres before the specs run; setup/global-setup.ts seeds the auth + fixture state. The suite is not part of the fast local gate (typecheck / lint / test) — it surfaces at PR CI, so expect responsive/wizard/nav reworks to flag here first.
Layout
setup/—test.ts(the suite'stest+expectentry point),global-setup.ts(auth + DB seeding),test-helpers.ts(shared login + navigation helpers).utils/— fixtures such asmock-dashboard-snapshot.ts.fixtures/— synthetic payloads a journey uploads, built in code rather than committed as blobs so the content stays reviewable (apple-health-export.ts).*.spec.ts— one spec per flow: auth/login/redirect, dashboard, charts, the medication-wizard cadences (medications-wizard-*), insights generation + scroll restoration, doctor report, settings, mobile-viewport consistency, locale switch, accessibility (a11y.spec.ts), and thev1427-*regression set.
Conventions
Import test and expect from ./setup/test, never from @playwright/test — types (Page, Route, …) still come from the package. The entry point extends Playwright's test with an automatic fixture that drops route handlers and page listeners after every test, so a handler left in flight cannot fail the test it belonged to once the context closes. src/__tests__/e2e-route-cleanup-guard.test.ts enforces the import boundary.
Assert against stable data-* attributes (data-slot, data-display-step, root display attrs), not viewport-dependent visible text. Responsive sm:hidden UI changes break getByText on desktop while the underlying element is still present — anchoring on data attributes keeps the specs stable across breakpoints. See ../CLAUDE.md.